The only truly Official Ritual of E.G.C. is Liber XV, the Gnostic Mass. However, the text of Liber XV alludes to the additional sacramental rites of baptism, confirmation, marriage, and ordination; implying Crowley's intent that the E.G.C. would eventually function as a Thelemic church, ministering to the various religious needs of congregations of Thelemites. Crowley's private notes toward a rite of baptism are extant. However, any liturgies he may have composed for the other rites mentioned have not been found. The "official" rituals given here were composed by E.G.C. clergy and approved by the Patriarch and the U.S. Primate. Approved rites for ordaining priests and priestesses are available to E.G.C. bishops. Bishops may submit sacramental rituals of their own composition to the Patriarch for review and approval.

The E.G.C., while entirely Thelemic in theology and doctrine, has its ceremonial roots in the French Gnostic Churches, and in the Western Liturgical Tradition in general. These rituals, like the Gnostic Mass itself, were composed with this in mind, and the text of Liber XV was used as the principle source of information for ritual development. Additional source material was taken from the Thelemic canon and the body of Crowley's writings. The rituals used by the old E.G.C. corporation under Patriarch McMurtry were used as structural precedents, and the rituals used by various branches of the French Gnostic Church were also reviewed, along with the writings of various authorities on the nature and traditions of sacramentalism and sacerdotalism such as J.G. Frazer, J.G.R. Forlong, E.O. James, E.S. Drower, and others.